/*
 * Copyright 2023 Ant Group CO., Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied.
 */

package com.antgroup.openspg.server.common.model;

import java.util.HashMap;
import java.util.Map;

/** A utility class for formatting log messages, using {} as placeholders. */
public class MessageFormatter {

  static final char DELIM_START = '{';
  static final char DELIM_STOP = '}';
  static final String DELIM_STR = "{}";
  private static final char ESCAPE_CHAR = '\\';

  public static String format(final String messagePattern, final Object... argArray) {
    if (messagePattern == null) {
      return null;
    }

    if (argArray == null) {
      return messagePattern;
    }

    int i = 0;
    int j;
    // use string builder for better multicore performance
    StringBuilder sbuf = new StringBuilder(messagePattern.length() + 50);

    int x;
    for (x = 0; x < argArray.length; x++) {

      j = messagePattern.indexOf(DELIM_STR, i);

      if (j == -1) {
        // no more variables
        if (i == 0) {
          // this is a simple string
          return messagePattern;
        } else {
          // add the tail string which contains no variables and return
          // the result.
          sbuf.append(messagePattern, i, messagePattern.length());
          return sbuf.toString();
        }
      } else {
        if (isEscapedDelimeter(messagePattern, j)) {
          if (!isDoubleEscaped(messagePattern, j)) {
            // DELIM_START was escaped, thus should not be incremented
            x--;
            sbuf.append(messagePattern, i, j - 1);
            sbuf.append(DELIM_START);
            i = j + 1;
          } else {
            // The escape character preceding the delimiter start is
            // itself escaped: "abc x:\\{}"
            // we have to consume one backward slash
            sbuf.append(messagePattern, i, j - 1);
            deeplyAppendParameter(sbuf, argArray[x], new HashMap<>(16));
            i = j + 2;
          }
        } else {
          // normal case
          sbuf.append(messagePattern, i, j);
          deeplyAppendParameter(sbuf, argArray[x], new HashMap<>(16));
          i = j + 2;
        }
      }
    }
    // append the characters following the last {} pair.
    sbuf.append(messagePattern, i, messagePattern.length());
    return sbuf.toString();
  }

  static boolean isEscapedDelimeter(String messagePattern, int delimeterStartIndex) {

    if (delimeterStartIndex == 0) {
      return false;
    }
    char potentialEscape = messagePattern.charAt(delimeterStartIndex - 1);
    if (potentialEscape == ESCAPE_CHAR) {
      return true;
    } else {
      return false;
    }
  }

  static boolean isDoubleEscaped(String messagePattern, int delimeterStartIndex) {
    final int startIndex = 2;
    if (delimeterStartIndex >= startIndex
        && messagePattern.charAt(delimeterStartIndex - startIndex) == ESCAPE_CHAR) {
      return true;
    } else {
      return false;
    }
  }

  /**
   * special treatment of array values was suggested by 'lizongbo'
   *
   * @param sbuf
   * @param o
   * @param seenMap
   */
  private static void deeplyAppendParameter(
      StringBuilder sbuf, Object o, Map<Object[], Object> seenMap) {
    if (o == null) {
      sbuf.append("null");
      return;
    }
    if (!o.getClass().isArray()) {
      safeObjectAppend(sbuf, o);
    } else {
      // check for primitive array types because they
      // unfortunately cannot be cast to Object[]
      if (o instanceof boolean[]) {
        booleanArrayAppend(sbuf, (boolean[]) o);
      } else if (o instanceof byte[]) {
        byteArrayAppend(sbuf, (byte[]) o);
      } else if (o instanceof char[]) {
        charArrayAppend(sbuf, (char[]) o);
      } else if (o instanceof short[]) {
        shortArrayAppend(sbuf, (short[]) o);
      } else if (o instanceof int[]) {
        intArrayAppend(sbuf, (int[]) o);
      } else if (o instanceof long[]) {
        longArrayAppend(sbuf, (long[]) o);
      } else if (o instanceof float[]) {
        floatArrayAppend(sbuf, (float[]) o);
      } else if (o instanceof double[]) {
        doubleArrayAppend(sbuf, (double[]) o);
      } else {
        objectArrayAppend(sbuf, (Object[]) o, seenMap);
      }
    }
  }

  private static void safeObjectAppend(StringBuilder sbuf, Object o) {
    try {
      String oAsString = o.toString();
      sbuf.append(oAsString);
    } catch (Throwable t) {
      sbuf.append("[FAILED toString()]");
    }
  }

  private static void objectArrayAppend(
      StringBuilder sbuf, Object[] a, Map<Object[], Object> seenMap) {
    sbuf.append('[');
    if (!seenMap.containsKey(a)) {
      seenMap.put(a, null);
      final int len = a.length;
      for (int i = 0; i < len; i++) {
        deeplyAppendParameter(sbuf, a[i], seenMap);
        if (i != len - 1) {
          sbuf.append(", ");
        }
      }
      // allow repeats in siblings
      seenMap.remove(a);
    } else {
      sbuf.append("...");
    }
    sbuf.append(']');
  }

  private static void booleanArrayAppend(StringBuilder sbuf, boolean[] a) {
    sbuf.append('[');
    final int len = a.length;
    for (int i = 0; i < len; i++) {
      sbuf.append(a[i]);
      if (i != len - 1) {
        sbuf.append(", ");
      }
    }
    sbuf.append(']');
  }

  private static void byteArrayAppend(StringBuilder sbuf, byte[] a) {
    sbuf.append('[');
    final int len = a.length;
    for (int i = 0; i < len; i++) {
      sbuf.append(a[i]);
      if (i != len - 1) {
        sbuf.append(", ");
      }
    }
    sbuf.append(']');
  }

  private static void charArrayAppend(StringBuilder sbuf, char[] a) {
    sbuf.append('[');
    final int len = a.length;
    for (int i = 0; i < len; i++) {
      sbuf.append(a[i]);
      if (i != len - 1) {
        sbuf.append(", ");
      }
    }
    sbuf.append(']');
  }

  private static void shortArrayAppend(StringBuilder sbuf, short[] a) {
    sbuf.append('[');
    final int len = a.length;
    for (int i = 0; i < len; i++) {
      sbuf.append(a[i]);
      if (i != len - 1) {
        sbuf.append(", ");
      }
    }
    sbuf.append(']');
  }

  private static void intArrayAppend(StringBuilder sbuf, int[] a) {
    sbuf.append('[');
    final int len = a.length;
    for (int i = 0; i < len; i++) {
      sbuf.append(a[i]);
      if (i != len - 1) {
        sbuf.append(", ");
      }
    }
    sbuf.append(']');
  }

  private static void longArrayAppend(StringBuilder sbuf, long[] a) {
    sbuf.append('[');
    final int len = a.length;
    for (int i = 0; i < len; i++) {
      sbuf.append(a[i]);
      if (i != len - 1) {
        sbuf.append(", ");
      }
    }
    sbuf.append(']');
  }

  private static void floatArrayAppend(StringBuilder sbuf, float[] a) {
    sbuf.append('[');
    final int len = a.length;
    for (int i = 0; i < len; i++) {
      sbuf.append(a[i]);
      if (i != len - 1) {
        sbuf.append(", ");
      }
    }
    sbuf.append(']');
  }

  private static void doubleArrayAppend(StringBuilder sbuf, double[] a) {
    sbuf.append('[');
    final int len = a.length;
    for (int i = 0; i < len; i++) {
      sbuf.append(a[i]);
      if (i != len - 1) {
        sbuf.append(", ");
      }
    }
    sbuf.append(']');
  }
}
